The "birds" may have the right but the cat has the claws

The tale of Stephens Island wrens, driven to extinction by a single cat owned by the local lighthouse keeper, has become a very popular legend among conservationists. The true facts behind this legend are not very different, as this unique nocturnal, flightless bird which lived nowhere else on the planet, was apparently exterminated by feral cats, although more than a single one. In fact, in Stephens Island cats became established in 1894, and after increasing in numbers dramatically affected several species. Stephens Island provides the classic example of the effect that predation by feral cats can have on an island land bird fauna. But this is a problem of global concern. In New Zealand, like in several other countries worldwide, islands experienced a rapid demise of the native land bird fauna due to cat predation. With just a little more care, and a thorough knowledge and understanding of the problem, many islands may have remained a safe haven for many species now disappeared. In this context, a new book published by Wiley "Free-ranging cats. Behavior, ecology, management" (by Stephen Spotte) provides a comprehensive and objective insight on the key topics related to the management of feral cats, addressing some fundamental issues for a correct analysis of the problem, including a review of the available information on the species' behavioral, biological and ecological features. The message is clear: we should stop further irreversible biodiversity losses due to cat predation, and we have the proper knowledge to deal with it. The book represents an optimal guidance tool for all those who are interested in a sound understanding of the issue, whether the focus be on cats or the wide range of little animals they prey upon, or both.

Cats are generalist predators that once introduced to the wild (or simply allowed to roam outdoor), can prey on a variety of native species, which may suffer severe population declines and even face extinction. On this regard, it makes no difference whether the cats are owned (in which case their impact might be even more subtle, because often unnoticed), stray or feral: as stated by George F. Will (American journalist, and author) The phrase "domestic cat" is an oxymoron. The result is that at the global level, cats are considered responsible for at least 14% of bird, mammal and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals and reptiles. The figures are impressive. In continental Australia and its offshore islands there are some 15-23 million feral cats which are estimated to eat about 75 million native mammals, reptiles, birds and even insects a night, more than 20 billion every year (see here for details). These astonishing figures are very similar to the results of a study made in the US. Also in Britain, estimates derived from scaling up local studies to the national level show that cats kill 25–29 million birds per year. It is easy to imagine how detrimental this species can be, considering that cats have been introduced to about 179,000 islands worldwide. According to another recent study, the impacts of feral cats is known from at least 120 different islands on at least 175 different species of vertebrates (25 reptiles, 123 birds, and 27 mammals), many of which are listed on the IUCN Red List. For example, in the Canary Islands, four species (one endemic bird — the Fuerteventura stonechat — and three endemic giant lizards) out of a total of 68 species (including invertebrates) identified as preys are considered threatened (for a review on the impact of cats and other invasive alien species, see the EEA technical report No 16/2012 discussed here). 

Stray cat in Rome © Photo: Riccardo Scalera

Cats are predators and are not to be blamed for this, but people and particularly cat owners could do more to prevent all this to happen. Prevention would be the most effective and easy option to ensure a reduced predation of cats on small mammals and birds (not to consider reptiles and amphibians, and a number of invertebrates) and raising awareness  should be a fundamental step in any nature conservation campaign. Otherwise, there is no doubt that the more effective way to prevent exacting such a heavy toll on native wildlife would be the implementation of policies to prevent the establishment of feral cats and their colonies in (semi)natural environments (see for example the Australian 2008 threat abatement plan predation by feral cats). This could save millions, if not billions, of birds and other animals, yet for many people might inevitably sound inconceivable. For those pet lovers who consider cats as family members, it may be difficult to believe that their companion pets may turn into such harmful threat to biodiversity. In fact, cat owners should make a special effort to acknowledge the problem and ensure keeping their pets indoors. Whenever this is not feasible, an alternative partial solution would be to fit cats with quick-release collars equipped with a bell or other deterrents (like bibs), which may significantly reduce predation rates on small mammals and birds (although cats can learn to silently stalk their prey anyway). 

The implementation of effective control measures on feral cats can be a challenging task. First of all, to maintain the necessary political/public support and funding, it is pivotal to consider humane, socially acceptable options, including ways to avoid or minimize methods that cause animal suffering or affect domestic cats, particularly for the inherent problems associated with the opposition of citizens and animal welfare groups. Disregarding the importance of these aspects might lead to the failure of the operations. In addition, some drawbacks have been reported in situations where cats have been removed without taking into proper account the presence of other introduced species (such as rabbits, rats or mice). The risk is that some problems linked to hyperpredation and predator release effect may create trophic cascades leading to rapid, landscape-wide ecosystem changes. It was the case of the removal of cats on the sub-Antarctic Macquarie Island, which resulted in a significant increase in rabbit abundance (formerly reduced by cat predation), which in turn led to substantial local- and landscape-scale changes in vegetation. Although this trophic cascade was predictable given the history of rabbit impacts via grazing on both this and other islands and was not entirely unexpected, its extent was not fully anticipated. This episode (see here for details) shows the importance of carefully assessing the risks of management interventions and planning for their indirect effects.

LIFE confirms financial support to alien species policy in Europe

On 18 June 2014 a new LIFE call has been launched, and invasive alien species (IAS) continue to be a priority issue for funding within the European Union (see previous post on the 2013 call here). The new LIFE Regulation, which establishes the EU financial Programme for the Environment and Climate Action, with a total budget set at 3.4 billion euro for the funding period 2014–2020, has been throughly revised. For example, the programme is now subdivided in the two sub-programmes Environment and Climate Action. Besides, to ensures both the necessary flexibility to achieve the LIFE Programme targets and objectives and the necessary stability for potential applicants to plan, prepare and submit proposals, a Multiannual Work Programme for 2014-17 has been adopted. 

LIFE aims at contributing to the achievement of the objectives and targets of the Europe 2020 Strategy, the 7th Union Environmental Action Programme and other relevant EU environment and climate strategies and plans. In this context, and as reported more in detail below, IAS are explicitly mentioned in the list of project topics implementing the environmental policy priorities under the three priority areas covered within the new "Environment" strand: environment and resource efficiency; nature and biodiversity; and environmental governance and information.  It is also worth remarking that now the newly revised programme – which is open to the participation of third countries and activities outside the EU - consists of a number of new categories of projects, including preparatory projects, integrated projects, technical assistance projects, capacity building projects. The project topics set in the multi-annual work programme refer to "traditional" projects in the Environment sub-programme. "Traditional" projects are indeed very similar to the old LIFE+ Nature, Biodiversity, Environment and Information projects, e.g. focusing on best practice, demonstration, pilot, and information projects. 

More in detail, within the  priority area “Nature and Biodiversity” the project topics which are given priority to contribute to Target 1 of the Biodiversity Strategy to 2020 to fully implement the Birds and Habitats Directives, thus under the Thematic priorities for Nature, include:

Projects targeting invasive alien species, where these are likely to deteriorate the conservation status of species (including birds) or habitat types of Community Interest in support of the Natura 2000 network 

Priority is also given to project topics focus on the implementation of Targets 2, 3, 4 and 5 of the Biodiversity Strategy to 2020, thus under the Thematic priorities for Biodiversity, such as:

Projects implementing actions targeting Invasive Alien Species (under Target 5 of the Biodiversity Strategy or in view of contributing to reaching the level of protection set out in descriptor 2 — Non-indigenous species of the Marine Strategy Framework Directive (1)) through actions testing and applying approaches aimed at:(a) preventing the introduction of invasive alien species, in particular by tackling pathways of unintentional introduction,(b) establishing an early warning and rapid response system, and(c) eradicating or controlling established invasive alien species on an appropriate spatial scale.

These projects shall address with their actions the three steps (prevention; early warning and rapid response; eradication/control) in a comprehensive framework, or, where one of the steps has already been addressed, their actions shall at least be clearly situated in a broader framework that links all three steps. They should be set up to improve existing — or introduce new — technical, administrative or legal frameworks on the relevant level; they should aim at preventing the broader establishment of IAS within the EU.

Finally, the project topics listed under the priority area "Environmental Governance and Information", include:

National and transnational awareness raising campaigns on invasive alien species (IAS) targeting the general public and key stakeholders including policy makers, businesses, and local, regional or national authorities.

LIFE projects focusing on IAS across the years (source: EEA report no.15/2012)

The experience of the last 20 years has shown that LIFE has been crucial to ensure the successful implementation of several activities focusing on IAS management and prevention, including new ways to address the wider IAS challenge (see "LIFE and alien species" report here). In fact, as shown in a recent report on biodiversity indicators (EEA report no.15/2012), both the number of LIFE projects funded and the relevant cost estimates have been markedly positive across the years. The relevant data have been used for the development of a set of response indicators, whose role should be primarily to track the measures being implemented to mitigate pressures and improve the state of biodiversity.  This trend has been interpreted as reflecting an increasing awareness of the IAS problem among EU institutions, wildlife managers, scientific institutions, and citizens, but could also indicate that within the EU, the problem with IAS is increasing.  

Thus, in the light of the recent developments regarding the EU regulation on the prevention and management of the introduction and spread of IAS, the new call and the overall novelties introduced within the new LIFE Regulation, are very welcome. In fact the new EU regulation on IAS seeks to address the problem in a comprehensive manner so as to protect native biodiversity and ecosystem services, as well as to minimize and mitigate the human health or economic impacts that these species can have. The IAS legislation now needs only to be formally approved by the Council of Ministers (see details here), and there is a clear need of dedicated financial resources for the implementation of the foreseen types of provision focusing on prevention, early warning and rapid response, and management.

For the 2014 call 132,8 million euro out of a total budget of 404,6 million euro are for nature and biodiversity only, including related governance and information. The deadline for submitting proposals is 16 October 2014. You can find further information, application forms and all official guidance documents here.

Changing soundscapes. The spread of parakeets in Europe

This is going to be another “noisy spring”. The melodious notes of native black birds, wrens and robins are being progressively replaced in many European towns by the frequent loud screeching calls of monk parakeets and rose ringed parakeets. The genuine “soundscape” of European towns is indeed rapidly changing, replaced by the exotic calls of parakeets, which are becoming a familiar sound in many European cities, particularly in urban areas and parklands. Roosting sites are sometimes spectacular, as they may often contain several hundred birds attracted from a wide area to just a few trees. Nevertheless the screeching calls of parakeets in Europe, rather than being considered a mere novel fascinating thing, should remind us of the actual and potential threats they represent. In the old continent parakeets are not native species, as they have created breeding colonies only recently, further to intentional releases or accidental escapes of animals traded at least since the 60's as cage birds. Like many other invasive alien species, their presence can be detrimental to the environment and human welfare.

Monk parakeet (Myiopsitta monachus) in a cage
© Photo: Riccardo Scalera

Take for example the rose-ringed parakeets. This native to the African continent south of the Sahara and to south Asia, is now the most widely introduced parrot in the world (including at least 12 countries in Europe). In Europe, besides being a clear noise nuisance as already considered in some residential areas, can have a major impact on biodiversity, agriculture and even health. In fact rose-ringed parakeets may have detrimental effects on native birds with which they may compete, particularly in those habitats where the number of cavities as breeding sites is a limiting factor regulating population densities of cavity-nesters (e.g. for species like Eurasian nuthatch,  kestrel, stock dove, western jackdaw and common starling). 

In Europe most rose-ringed parakeet populations were initially introduced in urban environments, thus the impact on agriculture has been historically limited. However, they are now extending their range into rural environments, thus increasing the potential to become agricultural pests. Although the reports of parakeet damage to agriculture are still few, there is clear evidence of significant damage to crops as well. For example, in the United Kingdom rose-ringed parakeets damage buds and blossoms of various trees and shrubs. For this reason conflicts are known with fruit growers that experienced damage to apple, pear, cherries and plums. In addition, this parakeet has been reported to have damaged vineyards by reducing the expected wine production. Also in Australia, where the species is not native, rose-ringed parakeets are known to cause severe damage to plantations by stripping the bark from young stems and killing the affected trees, thus locally changing the arboreal composition. On the other hand, in at least part of its native range this species is considered one of the most destructive bird pests for agriculture. In India and Pakistan, for example, there are extensive reports of crop damage. 

Rose-ringed parakeet eating plums in Versailles
(Psittacula krameri)  © Photo: Riccardo Scalera

Rose-ringed parakeets are also possible vectors for diseases, like Newcastle's disease and cryptosporidium, which could be harmful to poultry and might also have an impact on that industry. Moreover, they could affect humans in the case of psittacosis. In any case, the potential for the parakeets to become serious pests in the future has been highlighted, in fact there is concern that farming practices that adapt to global climate change and a warmer Europe will facilitate the continued expansion of parakeet populations. As a consequence, given the detrimental impacts of parakeets occurring outside their natural range, it would be useful to monitor existing wild and captive populations, and to improve legislation to prevent deliberate introductions and escapes. Moreover, depending on the risks posed, population control or eradication may be considered necessary to limit the spread of the species and the potential for further damage. But this might be not very popular. The experience with the monk parakeet control in London (described here) is a good example of the challenges and opportunities of this option in Europe, with a special focus on the social dimension of the problem represented by this South American parakeet.

A dedicated EU project – ParrotNet - is just being launched with the aim to create a European network focusing on the impacts, drivers and monitoring of invasive parrots in Europe, and promoting the understanding of relevant invasion dynamics and risks to agriculture and society. ParrotNet is a COST Action, led by the University of Kent, UK, and will provide funding for a 4-year research network (for further information see here). The project, comprising currently 14 European countries, will help to (i) better understand why some species such as parakeets are highly successful invaders, (ii) harmonise methodologies to predict agricultural, economic, societal and ecological impacts across Europe, and the means to mitigate them, (iii) create a virtual European Monitoring Centre for all invasive parrot species, and (iv) transfer results to policy and society.  This is a key attempt to prevent that Carson's prophesy of a “silent spring” will be replaced in the near future by a more and more insidious “noisy spring”.